1. Field of the Invention
This invention relates to a display apparatus for vehicle and a display method.
2. Background Art
There is a group of display devices called as Head-Up Display (HUD) as a display apparatus for vehicle. In these display apparatuses, an image presented by picture formation devices such as LCD (Liquid Crystal Display) or CRT (Cathode Ray Tube) is supplied to an observer driving a vehicle by reflecting the image on a half-translucent reflector such as a half-mirror through an optical system. By the half-translucent reflector, which is called as a combiner, the transmitted outside information and the reflected picture of the picture formation device are superimposed and supplied to the observer. As a result, the observer is allowed to visually identify the outside information and the picture information of the picture formation device simultaneously.
With respect to the display apparatus like this, it is strongly requested that the outside information defining the background is completely superimposed upon the presented picture information, for example, the presented picture information is placed to be projected at a position corresponding to spatial location of the outside information. Particularly, it is tried that route information is presented in a state of more matching with the outside information defining the background.
JP-A 2006-17626 discloses a technology presenting an image while changing the image size along a lapse of time with movement of a moving object so that the image is overlapped with a scene to be seen ahead a windscreen of the moving object.
However, in the conventional HUD, a subjective depth position (depth perception position) of the presented information coincides with a virtual image position observed as a virtual image, therefore, even if any presented information is given, it is difficult to coincide the depth perception position of the presented information with the real spatial location.
Distance characteristics of depth sensitivity due to various causes with respect to human depth sensitivity are reported in “Shojiro, Nagata; ”Visual Sensitivities to Cue for Depth Perception”, The Journal of the Institute of Image Information and Television Engineers, vol. 31, No. 8, pp. 649-655, 1977 (in Japanese), hereinafter referred to as Non-Patent Document 1.